The workshops grew out of Shelby's research on Underground Railroad founder Harriet Tubman, Martin Luther King Jr. and jazz legend Louis Armstrong. In February, Shelby took his family on a tour of the South to visit historical sites important to the civil rights movement - Memphis; Little Rock, Ark.; Jackson, Miss.; and Birmingham and Montgomery, Ala.

He lives in the Mission District with his partner, Vanessa Silva, their 7-month-old daughter, Billie, and Shelby's 7-year-old daughter, Kennedy, from a previous relationship.

I was born in Anchorage, Alaska. My dad was stationed there. Then we moved to Sacramento when he got transferred to McClellan Air Force Base.

My parents weren't professional musicians. They sang in church. So that was the sort of my musical DNA. My mom plays piano; she knows how to play all the spirituals. That for me was very grounding.

I went to Cal Arts in Los Angeles and studied bass with Charlie Haden and composition with James Newton. The bass is the foundation. Listen to reggae: That bass line tells you it's a reggae song. Listen to swing or blues, the same thing. The bass is like the heart beating involuntarily.

Everything else kind of centers around that pulse. So there's a lot of responsibility in the bass. It's the timekeeper.

Twenty years ago, I decided I wanted to only play acoustic bass. No amp. I wanted to develop a style that was almost the way a person would sing in a mike. And have all the components of that: the overtones, the attack, the subtleties and nuances.

I was losing those qualities with an amp. What you gain in amplification, I was losing in something very guttural, very natural and human that you can only get if you don't use an amp. The overtones aren't resonating naturally. They're going through some sort of box, some sort of equalizer.

Three years ago, a friend came over and he's like, "Man, you need a new bass" and sold me his German flat back. Over 100 years old. It makes a big difference: The wood, the way the neck is carved, the size of the bass, the strings. The tailpiece, the endpin. All the things you might think are just ornamentation are part of the entire sound emanating from that instrument.

My girlfriend plays guitar. My 7-year-old's been studying piano and violin. I play bass and a little piano, and we have sessions here, my family. Me and my daughter play together all the time.

Music has always been for me an extension of a lot of other things, like politics and history and teaching and social justice.

The first year (of my workshop), I did a program called Harriet Tubman and Jazz. I talked about the music that came out of slavery - field cries, work songs, blues hollers, spirituals - and how that music was a form of communication to give messages to slaves, to help along the Underground Railroad. I wanted to expose that to young people, to show how these early strains of music evolved into all of American music - from the early blues to hip-hop.

The second year was Dr. Martin Luther King Jr., and the third year Louis Armstrong. I told them about Armstrong: "Look, he was born to a prostitute, didn't know his father and yet he was able to overcome that. Let's listen to his music, but let's talk about his character."

Some of these kids have very challenging homes or in some cases no home at all. Those are the kids for whom a story like Louis Armstrong's resonates the most.